IQ scores
What an IQ of 100 means
An IQ of 100 is at the 50 percentile on the standard scale. It is the exact average: half of people score higher and half lower. It falls in the range usually labelled average.
IQ 100 at a glance
| Percentile | 50 |
| Rarity | 1 in 2 |
| Range | Average (about 50 in 100 of people) |
| Distance from average | None |
| Same result on SD 16 | 100 |
| Same result on SD 24 (Cattell) | 100 |
What it tells you
A score of 100 is in the average range, where half of all adults fall. Differences of a few points here are smaller than the margin of error of any test, so 100 and 105 are not meaningfully different results.
Most people in every occupation score in this range. Within it, things a test does not measure, such as persistence, knowledge and practice, matter far more than the number.
How sure can you be of a score of 100?
That depends on the test. On a long, supervised assessment the margin of error is a few points. On a short online test it is around ten, so a reported 100 means a true score probably somewhere between 89 and 111. That span runs from the 23 to the 77 percentile.
Scores also depend on the scale. If your 100 came from a test using a standard deviation of 16 or 24, it is not the same as 100 here; the percentile calculator converts between them.
Nearby scores
- IQ 95: 37 percentile.
- IQ 105: 63 percentile.
- The full IQ scale, with every range.